Hydraulic variable-speed gear



(No Model.) 3 Sheets-Sheet 1. L. DUNCAN. HYDRAULIC VARIABLE SPEED GEAR.

' No. 466,660. Patented Jan. 5, 1892.

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Jun [we as 3 Sheets-Sheet 3.

(No Model.)

L. DUN CAN.- HYDRAULIC VARIABLE SPEED GEAR.

PatentedJan. 5

UMTED, STATES j PATENT OFFICE.

Lou s DUNCAN, or BALTIMORE MARYLAND;

H YDRAULIC VARIABLE-SPEED GEAR.

SPECIFICATION forming part of Letters Patent No. 46,660, dated 1892." Application tiled December 10, 1390. Serial No. 874,140- -(Ro model.)

To all whom it may concern:

, Be it known that I, LOUIS DUNCAN, a citizen oi the United States, residing'at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Hydraulic Variable-Speed Gears; andl do hereby declare the following to be a full. clear, and exact description of the inventiomsueh as will enable others skilled in the art to which'it'appertains to make and use the same.

My invention relates to hydraulic motors and speed-regulators; and its object is the providing of an apparatus which will furnish a gearing whose ratio may be kept fixed or varied at will, and at the same time the great losshs due/to friction and angularity common in .m ultiple gearing may be largely diminished. 1 To accomplish these results -I couple together a hydraulic pump run by any convenient source of power and a hydraulic motor driven by the pump. Either the pump or the motor, or both, I have so adjusted that,

although the quantity of the fluid flowing through both will be the same, by altering either or both of their eccentricities the velocityrof flow of the liquid through the one or the other, or through both, may be altered at will, andthus their relative speeds may be changed.

' motive power, a lower, a higher, or avariable While my invention is applicable to most of the forms ofgearing, where, with a given rate of speed is desired, I will illustrate its use as applied to the gearing on the axles of electric cars, where it isdesired to keep up a high rate of speed in the electric motor and regulate the speed of'the car-wheels at will.

Reference is bad to the accompanyingdrawings, wherein Figure 1 represents a vertical section through the axle and driving-gear of the-car. Fig. 2 represents a vertical section through the pump along the line a: a: of Fig. 1. Fig. 3 represents a vertical section through the hydraulic motor along the ,line g. y of ig. 1. Figs. 4 and 5 represent cross-sections of two positions of a wo-way valve connecting the pump and the iydraulic motor. Fig. 6 represents a vertical longitudinal section showing a modification of my device wherein I use a fixed pump" and adjustable motor.- l-i g. 7 represents a vertical longitudinal sccmm showing a modification of my device wherein I use an adjustable pump and adj ustable motor. Fig. 8 represents asectional elevationofan electrical motor having its revolving armature connected to thepump of variable eccentricity, which latter is mounted on the same shaft with and connected to a motor also of variable eccentricity.

A represents thecar-axle.

B and B represents sleeves having sliding" paddles C and O, forced out by springs c I against the interior surface of the cylinders D and D, respectively. The sleeve-B slips over the shaft A, either of which is free to revolve, independently of the other, while the sleeve B is keyed to the shaft A, as at b.

The cylinder D, surrounding the paddles C 0, slides vertically (or horizontally or in any other direction, if preferable) in guides E E, Fig. 2, and is controlled by the screw F and hand-wheel). The lower end of this screw is revolubly attached to the said ringD', while the hand-wheel f comes inside the car.

- Since the shaft A is fixed relative to the.

the turning effect of the liquid, maybe altered as with the pump, if desired. This is shown in Figs.,5 and 6, wherein thehand-wheel f, attached .to'the screw F, moves the ring D in the motor in a direction at right angles to the axle A. v

- AI and II are the cylinder-heads for the outer ends of the pump and hydraulic motor,

respectively, and K and K are the stuflingboxes for the same.

Between the pump and the hydraulic motor I have shown a disk G, containing the passages for the fluid and the reversing-valve M The fluid, is forced by the pump through the motor and returning by-regurgitating-passages to the pump, thus forming a closed fluidei rcuit. These passages are not shown in Fi g.

l. but are illustrated by the full and dotted lines in Figs. 4 and 5, while in Figs. 2 and 3 the orifices g and g g and g g, and g and g, and g, are at the ends of the same channels, respectively. Thus the liquid leaves the pump by g and entering the motor by g, pushes the paddles around until it escapes at y Hence it returns through the regurskilled mechanic. I do not claim it as a partof my invention.

Air-chambers may be supplied to any parts I of my liquid-circuit in order to form a cushof my invention ion and insure uniformity of action.

The pump is run by means of an electrodynamie motor B'j'Any form of motor may be adopted, with revolving armature P, sleeve N, and sleeve B rigidly attached the one to the other. The electric connections and other features of the electric motor, for the sake of clearness in the drawings, are omitted.

. Q and Q are the car-wheels.

The operation of my device is briefly this:

The electro-dynamic motor drives the pump.

The fluid from the pump runs the motor, and so turns'the car-axle with the wheels Q and Q. It will be readily seen that it is not necessary to have either the ,original motive power, the pump, or the hydraulic motor in juxtaposition; but in this present application they were so arranged in order to obtain the compactness necessary in the cramped space beneath the car.

My device may evidently be applied to one or more axles of the car. d t

It will be seen thatby shitting the cylinder D slowly from its posit-ion concentric with A sudden jars in starting will be avoided, the strain coming gradually upon thefhydraulic motor.. v

The numberof revolutions of the hydraulic motor will depend upoh the eccentricity of the motor and the quantity'of liquid passing through it. The ratio between this number of revolutions and the quantity of fluid I will call theispeed ratio. Since it the eccentricity be constant the speed of the hydraulic motor will vary with the quantity of liquid flowing through it in a given time, it will be readily seen that it the throwing capacity of the pump be increased the speed of the motor will increase. If the 'said capacity of the pump be decreased, the speed of the motor will be decreased, a'hd when the pump throws uo'liquid the effect on the hydraulic motor will be rnil. Moreover, it will be also:

clear that if the flow of liquid be reversed ing the motor the said motor will be impelled in the opposite directiomand hence it it be;

attached to a car-axle revolving in one di-,

motion the revm'sal of the flow of li uid wi l energy to the be equivalent to putting on brakes until the car is brought to a standstill, \vhenit will'begin to move backward; but for use asahrake it will be' necessary to have air-chambers over the passages bet-ween the pump and the hydraulic motor, for otherwise the incompressibility of the liquid would cause therapidlymoving motor to work the pump, and so suddenly reverse the electric motor with possibly disastrous results. V

Another met-hodot using my gear as a brake when used on car-axlesis as follows: \Yhcn the ear is' in niotiomsuppose the eccentricity of the pumpis decreased. The momentum of the car will tend' to make the hydraulic n10- .tor continue at the samespeed, and fora while the condition of things is reversed and the motor will tend to drive the pump. As i the speed ratio of the motor remains the same while that of the pump is increased, the speed of the pump will tend to increase, and therev ,fore the speed of the electric-motor armature. The field of theelectr nnotor being of constant strength and the speed increasing, the counter electro-motive force of the motor will become greater than that of the line and the motor becomes a dynamo, returning line and braking the car at the same time. W hen the eccentricity of the pump is zero, the h dra-.ulic motor cannot possibly revolve.v It is lock ed. 'hen going down a grade, the motor may be used as a dynamo again, and the eccentricity of the hydraulic pump may be shifted to allow the car to descend at any desired rate, the system acting as a brake and returning the surplus energy to the line or the storage-batteries. This, it will be noted, does away-with the necessity forair-chambers.

\Vhile I have shown the aperture for tho flow of liquids in the hydraulic motor as con- .stant and that in,the pump as variable,'it will be readily seen that similar variations in speed would be produced by varying the cocentricity of the motor, and that should the eccentricity of both pump and motor be variable these variations may be made to an;- ment or to neutralize each other, as may be desired.

\Yhile I have shown my device as applied to the axles of electric cars, it may be readily seen that it is suitable for many other forms of gearing, notably in 'lathes, saw-mill feed mechanism, and in other machines where a variable speed is required.

'It will be apparent that the pump and by. draulic motor may be any distance (even miles) apart if connect-ed bysuitable pipe and valve, and that the pump may be driven by a running stream or any other motive power and the water from the hydraulic momyself tothe construction described and shown; but

What I do claim, and desire to secure by Letters Patent of the United States, is-

1. In a variable-speed gear, the combination, with a rotary eccentric piston-pump and means for altering the eccentricity of said pump at will, of a hydraulic motor and a 'closed liquid-circuit connecting said pump and said motor, substantially as described.

2. In a variable-speed gear, the combination, with a shaft, of a rotary eccentric piston-pump and hydraulic motor, both mounted thereon, the cylinder inclosing said pump being movable at right angles to its axis, a device for moving said cylinder in said dimotion and so altering the eccentricityof the said pump, and a closed liquid-circuit connecting said pump and said. motor, substantially. as described.

3. In a variable-speed gear, the combination of a rotary pump having extensory pad- .dles rotating"- within a cylinder, said cylinder being capable of adjustment in a plane at right angles to the plane of the said paddles, with a hydraulic motor receiving its fluid from the said pump, and a closed liquid-circuit between said pump and motor, substantially as described.

4. In a rotary pump, the combination of a screw revolubly attached to said cylinder between said guides and engaging a fixed nut,

. substantially-as described.

6. In avariable-spee'd gear, the combination I of a hydraulic motor attached to a drivingshaft and a rotary pump connected to said motor, said pump fitting loosely on said shaft and being driven by any source of power.

7. In a variable-speed gear, the combination of a hydraulic motor attached to a drivingshaft and arotary eccentric piston-pump with eccentricity variable at will connected to said motor, said pump fitting loosely on said shaft and being driven by any source of power.

8. In a variable-speed gear, the combination of a hydraulic motor rigidly attached to a driving-shaft, a rotary pump fitting loosely on the said shaft, and an electric motor also on the said shaft and connected to the said pump, substantially as described.

9. In a variable-speed gear, .the combination of a hydraulic motor rigidly attached to adriving-shaft, a rotary eccentric piston-pump with eccentricity variable at will fitting loosely on the said shaft, and an electric motor also on said shaft and connected to said pump, substantially as described.

10. In a variable-speed gear for electric cars, the combination of a hydraulic motor rigidly attached to one of the axles of a car, a hydraulic pump'fitting loosely on the said axle, and an electric motor also on the said axle and connected to said pump, substantially as described.

11. In a variable-speed gear for electric cars, the combination of the shaft A, an electro-dynam'ic motor mounted thereon, sleeves N and B, fitting loosely thereon,'sleeve H, keyed thereon, paddles (J and 0, cylinders D and D, and passages between the pump and the motor for the fluid, substantially as described.

12. In a variable-speed gear for electric cars, the combination of the shaft A, an electro-dynamic motor mounted thereon, sleeves N and B, fitting loosely thereon, sleeve B, keyed thereon, paddles C and 0, cylinders D and D, guides E and E, and a closed circuit between the pump and the motor for the fluid, substantially as described.

In testimony whereof I afiix my signature in presence of two witnesses.

LOUIS DUNCAN. Witnesses:

W. F. HASSON, RANDOLPH WINsLow. 

